Methods. Consecutive patients with OA and RA with hand and wrist involvement were studied. Clinical assessment, physical examination, hand and wrist radiography and laboratory tests were carried out. After performing 0.2T MRI (T(1), T(2) and short time inversion recovery sequences) of the dominant hand and wrist, images were recorded in a US machine equipped with a virtual navigator system. Ultrasonography was performed in the same joints using an 18 MHz linear probe. Image MRI/US superposition was carried out, with real-time contemporary visualization of the US and related MRI images. Randomly selected stored images of different joints were subsequently re-analysed by a different operator. Concordance between the static and dynamic evaluations was assessed. Results. Nine patients (six with OA and three with RA) were studied. The real-time MRI/US overlap provided fusion images of both tools. A striking concordance in the visualization of the bony profile was found with evidence of pronounced osteophytes in OA and bone erosions in RA. The analysis of stored selected images demonstrated a high concordance between real-time and static assessment. Conclusion. MRI/US fusion imaging gives a composite set of information with accurate anatomical correlations.